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Sixth International Conference on Power Electronics and Drive systems, PEDS 2005

作者： Guo, Wei Zhao, Zhengmlng Department of Electrical Engineering Tsinghua University State Key Laboratory of Control and Simulation of Power System and Generation Equipment Beijing China

ISBN: (纸本)0780392965

Two axially-laminated Glued Axially-Laminated Synchronous Reluctance Permanent Magnetic (SR-PM) motors are designed and tested. Compared to general Axially-Laminated Synchronous Reluctance (SR) motors, the steel bracket is replaced with iron lamination for reduction of iron loss in rotor. The axially-laminated Iron and magnet are glued on the bracket with high strength cement with the help of special clamping device. Then the rotor Is grinded to the cylinder and a stainless steel rotor sleeve is added to enhance the strength. The design flow starts with initial sizes trade-off and static performance analysis followed by high speed performance validation and dynamic operation simulations. The electromagnetic parameters measurement, no-load and load test are carried out on test bed to verify the design. The comparison of these two sample motors are given for future design reference. It can be concluded that very poor max energy product PM material is not a good choice for application that requires high power density. © 2005 IEEE.

关键词： Reluctance motors

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A computer control and monitoring system for high power converters

A computer control and monitoring system for high power conv...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

作者： Rong, Yi Zhenming, Zhao Xiaoying, Sun Liqiang, Yuan Jue, Qian Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100086 China

ISBN: (纸本)7506274078

Computer control and monitoring system (CCMS) is quite important for high power converters (HPCs) operation. This paper presents a novel CCMS, which integrates a database management system (DBMS) into the monitoring software to get the beneficial features such as simple configuration and compact structure. In its communication system, an advanced optical fiber communication (OFC) technology is applied and priority-based communications is proposed to improve the reliability and the real time of the communications. Furthermore, a friendly standard Windows human-machine interface (HMI) is provided. The reliability and performance of the system are verified by system tests and practical operations.

关键词： Power converters

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The analysis of stator MMF and the calculation of rotor losses in a 12-phase high speed asynchronous generator

The analysis of stator MMF and the calculation of rotor loss...

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ICEMS 2005: 8th International Conference on Electrical Machines and systems

作者： Cheng, Luo Xiangheng, Wang Puqi, Ning Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing 100084 China

ISBN: (纸本)7506274078

To research the influence of multi-phase winding to generators and calculate the losses in solid rotors, the stator mint of a 12-phase asynchronous generator have been well analyzed and finite element method by ANSYS software has been applied to get the accurate losses in the rotor through both harmonic and transient 2-D analysis. The relationship between stator harmonic current and stator harmonic mint has been deduced and proved through ANSYS software to some extent, and rotor losses produced by both stator fundamental current and stator total current have also been obtained and compared. The results show that 12-phase stator winding with appropriate short pitch can effectively eliminate or reduce many mmf produced by stator fundamental and harmonic current and rotor losses are mainly produced by stator fundamental current.

关键词： Asynchronous generators

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PEEC method for modeling current distribution in grounding plane

PEEC method for modeling current distribution in grounding p...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

作者： Hau, Beibei Sun, Xudong Jiang, Jianguo State Key Laboratory of Control and Simulation of Power System and Generation Equipment Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)7506274078

In view of the impossibility of current measurement in actual grounding plane in power electronic equipment, an equivalent circuit model is set up in this paper using the partial element equivalent circuit (PEEC) method to simulate and calculate current distribution in grounding plane. The inductance parameters calculated are fairly coincident with experiment results, and some conclusions of current distribution are summarized. It is shown that the equivalent circuit model using PEEC method presented in this paper is a feasible and promising way to model and calculate current distribution in grounding plane.

关键词： Electric load distribution

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A novel nonlinear control for stability improvement in HVDC light system

A novel nonlinear control for stability improvement in HVDC ...

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2005 IEEE Power engineering Society General Meeting

作者： Li, Guo-Jie Ruan, Siye Peng, Lin Sun, Yuanzhang Li, Xiong State Key Laboratory of Power System Tsinghua University Beijing China Dept. of Electrical Engineering Tsinghua University China Tsinghua Univ. Dynamic Simulation Power System Lab.

ISBN: (纸本)078039156X

HVDC Light is more and more concerned recently to improve power system stability due to controllability of its IGBT valve. In this paper, a model of HVDC Light system will be established and analyzed. And a nonlinear control to enhance HVDC Light system stability is proposed. The digital simulation results show that the proposed nonlinear control is effective to damp system oscillations and enhance system stability. Furthermore, digital simulation studies will be conducted using the well-established PSCAD/EMTDC software package to show the effectiveness of the proposed nonlinear controller in damping oscillations when plow flow reversed. ©2005 IEEE.

关键词： Nonlinear control systems

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A new trust region algorithm for image restoration

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Science China Mathematics 2005年第2期48卷 169-184页

作者： WEN Zaiwen & WANG Yanfei state key laboratory of Scientific engineering Computing, institute of Computational Mathematics and Scientific/engineering Computing, Academy of Mathematics and system Sciences, Chinese Academy of Sciences, beijing 100080, China National key laboratory on Remote Sensing Science, institute of Remote Sensing Applications, Chinese Academy of Sciences, beijing 100101, China 1. State Key Laboratory of Scientific Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences 100080 Beijing China 2. National Key Laboratory on Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China

The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (LSE) method. But the LSE method is unstable in practical applications. A popular way to overcome instability is the Tikhonov regularization. However, difficulties will encounter when adjusting the so-called regularization parameter a. Moreover, how to truncate the iteration at appropriate steps is also challenging. In this paper we use the trust region method to deal with the image restoration problem, meanwhile, the trust region subproblem is solved by the truncated Lanczos method and the preconditioned truncated Lanczos method. We also develop a fast algorithm for evaluating the Kronecker matrix-vector product when the matrix is banded. The trust region method is very stable and robust, and it has the nice property of updating the trust region automatically. This releases us from tedious finding the regularization parameters and truncation levels. Some numerical tests on remotely sensed images are given to show that the trust region method is promising.

关键词： trust region algorithm, image restoration, Lanczos method, Kronecker matrix-vector product, preconditioning.

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Accurate flux observer based on distributed multi-processor in MV adjustable speed drive systems

Accurate flux observer based on distributed multi-processor ...

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ICEMS 2005: 8th International Conference on Electrical Machines and systems

作者： Shu, Liu Jianzheng, Liu Zhengming, Zhao Liqiang, Yuan Hua, Bai Haitao, Zhang Department of Electrical Engineering and Applied Electronic Technology State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China

ISBN: (纸本)7506274078

This paper presents an accurate flux observer used in distributed multi-processor (DMP) adjustable speed drive systems. The stator flux linkage is estimated with a full-order observer, while the rotor speed is identified by using Lyapunov theorem. In order to improve the system performance in a wide speed range, the stator resistance is estimated simultaneously. In this paper, the structure of the DMP system, the principle of the full-order observer and the method for identifying the rotor speed and state resistance are all described in details. Relevant simulation results based on MATLAB/SIMULINK are given to prove the performance of the method. Experiments of a real system also verify the feasibility of this scheme.

关键词： Microprocessor chips

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Infinitely Many Symmetries of Konopelchenko-Dubrovsky Equation

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Communications in Theoretical Physics 2005年第3X期44卷 385-388页

作者： LI Zhi-Fang RUAN Hang-Yu Department of Physics Ningbo University Ningbo 315211 China Nonlinear Science Center and Physics Department of Ningbo University Ningbo 315211 China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific Engineering Computing Academy of Mathematics and System Sciences the Chinese Academy of Sciences P.O. Box 2719 Beijing 100080 China

A set of generalized symmetries with arbitrary functions of t for the Konopelchenko-Dubrovsky (KD)equation in 2+1 space dimensions is given by using a direct method called formal function series method presented by Lo... 详细信息

关键词： formal function series method Konopelchenko-Dubrovsky equation infinite dimensional generalized ω∞ algebra

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Optimum parameters and maximum torque performances of the synchronous reluctance machine

Optimum parameters and maximum torque performances of the sy...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Wang Shijing Zhao Zhengming Guo Wei State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

The permanent magnet assisted synchronous reluctance (SR-PM) machine can not only offer higher torque capacity and improved power factors compared with the conventional synchronous reluctance machine, but also own wider adjustable speed range compared with the permanent magnet machine. This paper presents a new method to optimize the key parameters of the machine under keeping the torque of the machine as large as possible by controlling the stator current. Nonlinear optimization and functional analysis are used to obtain the maximal torque at a certain speed. The investigation of many groups of the parameter data shows that the performance of a machine is influenced by various factors such as magnetic materials, the quantities of the material in the rotor, the turns of windings in the stator and so on. The best one should be chosen for applications. The trend of all the curves verifies the simulation results.

关键词： Reluctance machines Magnetic materials Permanent magnets Reactive power Permanent magnet machines Optimization methods Torque control Functional analysis Stator windings Machine windings

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simulation, Test and Analysis of Three-phase Short-Circuit Braking in IGCT-based MV Adjustable Speed Drive systems

Simulation, Test and Analysis of Three-phase Short-Circuit B...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Zhang Haitao Zhao Zhengming Yuan Liqiang Bai Hua State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

In the medium voltage adjustable speed drive (MV-ASD) systems, low switching frequency results in high harmonics in the output voltage waveform, which is harmful to the isolation of the induction motor. Therefore, the power filter is usually set between inverter and motor. However, self-excitation oscillation easily occurs under this structure due to the filter capacitor, which could continuously bring up the DC-link voltage of the inverter, and even destroy the devices in inverters. One of the effective ways to eliminate the self-excitation oscillation is to set the inverter to three-phase short-circuit braking state, which is described and analyzed in detail in this paper. Three-phase short-circuit braking could be easily realized in the inverter-motor system. It can be verified by both simulation based on PSIM and test results that this is an efficient way in real applications. Finally, the characteristics of the short-circuit braking is summarized and beneficial suggestions on using this braking method are presented

关键词： Analytical models system testing Variable speed drives Inverters Power harmonic filters Medium voltage Switching frequency Induction motors Power filters Capacitors

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